This is a request for an NIMH Physician Scientist Award. The first two years focus on providing the awardee with training and supervison in the areas of (1) neuropsychopharmacology. Particularly with ragard to catecholamiane function in children, (2) the neurobiological processes associated with neurotransmitter function, (3) the relevent laboratory methodology of High performance-Liquid chromatography, Mass Spectrometry and enzymatic assays, and (4) measurement of attention and impulse control in children via standardize computer laboratory tools. In the last three years, this knowledge will be used to carry out a researach project under the direction of the sponsor and research advisor. The study will compare four groups of boys diagnosed by structured interview: (1) Attention Deficit Disorder (ADD) only, (2) ADD with concurrent Conduct Disorder, (3) ADD with concurrent Overanxious of the child's behavior using a standardized scoring system, and cognitive testing will be obtained at baseline. Each subject with ADD will then particiapte in a double-blind medication trail of two dosage levels of methylphenidate and imipramine. The study will examine if (1) differences in noradrenergic functioning exist between the three subgroups of ADD and the Overanxious group, and (2) children with ADD will respond differently to imipramine or methylphenidate based on the presence of conduct or anxiety symptoms.